Glossary of Steel Terms

Glossary of Steel Terms

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Face Centered (concerning cubic space lattices)
Having equivalent points at the corners of the unit cell and at the centers of its six faces. A face-centered cubic space lattice is characteristic of one of the slose-packed arrangements of equal hard spheres.

Fatigue
The phenomenon leading to fracture under repeated or fluctuating stresses having a maximum value less than the tensile strength of the material. Fatigue fractures are progressive, beginning as minute cracks that grow under the action of the fluctuating stress.

Fatigue
The phenomenon leading to fracture under repeated or fluctuating stress. Fatigue fractures are progressive beginning as minute cracks and grow under the action of fluctuating stress.

Fatigue
The phenomenon leading to fracture under repeatef or fluctuating stresses (having maximum value less than the tensile strength of the material).

Fatigue Life
The number of cycles of stress that can be sustained prior to failure for a stated test condition.

Fatigue Limit
The maximum stress below which a materiel can presumable endure an infinite number of stress cycles. If the stress is not completely reversed, the value of the mean stress, the minimum stress or the stress ratio should be stated.

Fatigue Strength
The maximum stress that can be sustained for a specified number of cycles without failure, the stress being completely reversed within each cycle unless otherwise stated.

Ferrite
A solid solution of one or more elements in body-centered cubic iron. Unless otherwise designated (for instance, as chromium ferrite), the solute is generally assumed to be carbon. On some equilibrium diagrams ther are two ferrite regions separated by an austenite area. The lower area is alpha ferrite; the upper, delta ferrite. If there is no designation, alpha ferrite is assumed.

Ferrite
Generally, a solid solution of one or more alloying elements in the bcc polymorph of iron ( -Fe). Specifically, in carbon steels, the interstitial solid solution of carbon in -Fe.

Ferrite Banding
Parallel bands of free ferrite aligned in the direction of working. Sometimes referred to a ferrite streaks.

Ferrite-pearlite Banding
Inhomogeneous distribution of ferrite and pearlite aligned in filaments or plates parallel to the direction of working.

Ferritic Grain Size
The grain size of the ferric matrix of a steel.

Ferro-Manganese
An alloy of iron and manganese (80% manganese) used in making additions of manganese to steel or cast-iron. Ferroalloy, An alloy of iron with a sufficient amount of some element or elements such as manganese, chromium, or vanadium for use as a means in adding these elements into molten steel.

Ferrous
Related to iron (derived from the Latin ferrum). Ferrous alloys are, therfore, iron base alloys.

Fiber
(1) The characteristic of wrought metal that indicates directional properties. It is revealed by etching a longitudinal section or manifested by the fibrous appearance of a fracture. It is caused chiefly by extension of the constituents of the metal, both metallic and nonmetallic, in the direction of working. (2) The pattern of preferred orientation of metal crystal after a given deformation process.

Fiber or Fibre
Direction in which metals have been caused to flow, as by rolling, with microscopic evidence in the form of fibrous appearance in the direction of flow.

Fiber Stress
Unit stress which exists at any given point in a structural element subjected to load; given as load per unit area.

Fiber Stress
Local stress through a small area (a point or line) on a section where the stress is not uniform, as in a beam under a bending load.

Fibrous Fracture
A fracture whose surface is characterized by a dull gray or silky appearance.

Filed Edges
Finished edges, the final contours of which are produced by drawing the strip over a series of small steel files. This is the usual and accepted method of dressing the edges of annealed spring steel strip after slitting in cases where edgewise slitting cracks are objectionable or slitting burr is to be removed.

Filler Metal
A third material that is melted concurrently with the parent metal during fusion or braze welding. It is usually, but not necessarily, of different composition from the parent metals.

Finery
A charcoal-fueled hearth furnace used in early processes for converting cast iron to wrought iron by melting and oxidizing it in an air blast, then repeatedly oxidizing the product in the presence of a slag. The carbon oxidizes more rapidly than the iron so that a wrought iron of low carbon content is produced.

Finished Steel
Steel that is ready for the market without further work or treatment. Blooms, billets, slabs, sheet bars, and wire rods are termed semi-finished produced by the in-the-line thermal treatment following electrodeposition.

Finishing Temperature
The temperature at which hot working is completed.

Finishing Temperature
Temperature of final hot-working of a metal.

Fish eyes
Areas on a fractured steel surface having a characteristic white crystalline appearance.

Flakes
Short discontinuous internal fissures in ferrous metals attributed to stresses produced by lacalized transformation and decreased solubility of hydrogen during cooling after hot working. In a fractured surface, flakes appear as bright silvery areas; on an etched surface thay appear as short discontinuous cracks. Also called shatter cracks and snowflakes.

Flame Annealing
Annealing in which the heat is applied directly by a flame.

Flame Annealing
A process of softening a metal by the application of heat from a high-temperature flame.

Flame Hardening
A process of hardening a ferrous alloy by heating it above the transformation range by means of a high-temperature flame, and then cooling as required.

Flame Hardening
Quench hardening in which the heat is applied directly by a flame.

Flapper Valve Steel
An extremely flat, very smooth, very accurate to gage, polished, hardened and tempered spring steel produced from approximately 1.15 carbon. The name is derived from its common and principle usage.

Flare Test
A test applied to tubing, involving a tapered expansion over a cone. Similar to pin expansion test.

Flash
(1) In forging, the excess metal forced between the upper and lower dies. (2) In resistance butt welding, a fin formed perpendicular to the direction of applied pressure.

Flash
(1) In forging, the excess metal forced between the upper and lower dies. (2) In die casting, the fin of metal which results form leakage between the mating die surfaces. (3) In resistance butt welding, a fin formed perpendicular to the direction of applied pressure.

Flash Welding
A resistance butt welding process in which the weld is produced over the entire abutting surface by pressure and heat, the heat being produced by electric arcs between the members being welded.

Flat Latch Needle Steel
Supplied cold rolled and annealed. Carbon content .85. Supplied both in coil and flat length. Used to make flat latch needles which are used in the manufacture of knitted goods.

Flat Wire
A flat Cold Rolled, prepared edge section up to 1 1/4 wide, rectangular in shape. Generally produced from hot rolled rods or specially prepared round wire by one or more cold rolling operations, primarily for the purpose of obtaining the size and section desired. May also be produced by slitting cold rolled flat metal to desired with followed by edge dressing.

Flow Lines
(1) Texture showing the direction of metal flow during hot or cold working. Flow lines often can be revealed by etching the surface or a section of a metal part. (2) In mechanical metallurgy, paths followed by volume elements of metal during deformation.

Flow Stress
The shear stress required to cause plastic deformation of solid metals.

Flow Stress
The uniaxial true stress required to cause plastic deformation at a specified value of strain.

Flowlines
Always visible to a greater or less degree when a longitudinal section has been subjected to Macro etching, indicating the direction of working or rolling.

Fluting
Kinking or breakage due to curving of metal strip on a radius so small, with relation to thickness, as to stretch the outer surface above its elastic limit. Not to be confused with the specific product, Fluted Tubes.

Flux
(1) In refining, a material used to remove undesirable substances as a molten mixture. It may also be used as a protective covering for molten metal. (2) In welding, a material used to prevent the formation of, or to dissolve and facilitate the removal of, oxides and other undesirable substances.

Foil
Metal in sheet form less than 0.006 in. in thickness.

Foil
Metal in any width but no more than about 0.005 thick.

Folds
Defects caused in metal by continued fabrication of overlapping surfaces.

Forge Welding
Welding hot metal by applying pressure or blows.

Forging
Plastically deforming metal, usually hot, into desired shapes with compressive force, with or without dies.

Forging
Plastically deforming metal, usually hot, into desired shapes with compressive force, with or without dies.

Fractography
Descriptive treatment of fracture, especially in metals, with specific reference to photographs of the fracture surface. Macrofractography involves photographs at low magnification; microfractography, at high magnification.

Fractography
Descriptive treatment of fracture, especially in metal, with specific reference to photography of the fracture surface.

Fracture
Surface appearance of metals when broken.

Fracture Test
Nicking and breaking a bar by means of sudden impact, to enable macroscopic study of the fractured surface.

Fracture Test
Breaking a specimen and examining the fractured surface with the unaided eye or with a low-power microscope to determine such things as composition, grain size, case depth, soundness, and presence of defects.

Fragmentation
The subdivision of a grain into small discrete crystallites outlined by a heavily deformed network of intersecting slip bands as a result of cold working. These small crystals or fragments differ from one another in orientation and tend to rotate to a stable orientation detemined by the slip systems.

Free Machining
Pertains to the machining characteristics of an alloy to which one or more ingredients have been introduced to produce small broken chips, low power consumption, better surface finish or longer tool life.

Free Machining
Pertains to the machining characteristics of an alloy to which an ingredient has been introduced to give small broken chips, lower power consumption, better surface finish, and longer tool life; among such additions are sulfur or lead to steel, lead to brass, lead and bismuth to aluminum, and sulfur or selenium to stainless steel.

Fretting (Fretting Corrosion)
Action that results in surface damage, especially in a corrosive environment, when there is relative motion between solid surfaces in contact under pressure.

Friction Gouges or Scratches
A series of relatively short surface scratches variable in form and severity. Refer to Galling.

Full Annealing
Annealing a ferrous alloy by austenitizing and then cooling slowly through the transformation range. The austenitizing temperature to hypoeutectoid steel is usually above Ac3; and for hypereutectoid steel, usually between Ac1 and Ac (cm).

Full Annealing
Used principally on iron and steel, means heating the metal to about 100 (degrees) F. above the critical temperature range, followed by soaking at this point and slow cooling below the critical temperature.

Full Annealing (ferrous materials)
An annealing treatment in which a steel is ausenitized by heating to a temperature above the upper critical temperature (A3 or Acm) and then cooled slowly to room temperature. A typical cooling rate would be 210F/h 100 C/h. Compare normalizing. Use of the term annealing without qualification implies full annealing.

Full Finish Plate
Steel sheet or strip, reduced either hot or cold, cleaned, annealed, and then cold-rolled to a bright finish.

Full Hard Temper
(A) (No. 1 Temper) In low carbon sheet or strip steel, stiff and springy, not suitable for bending in any direction. It is the hardest temper obtainable by hard cold rolling. (B) In Stainless Steel Strip, tempers are based on minimum tensile or yield strength. For Chromium-Nickel grades Full Hard temper is 185,000 TS, 140,000 YS Min. Term also used in connection with copper base alloys and considered synonymous with Hard Temper.

Fusion Welding
Any welding process in which fusion is employed to complete the weld.